A heat exchanger including multiple cores and spacer portions arranged between bonded surfaces of the adjacent cores is known in general. A heat exchanger like this is disclosed in Japanese Patent Laying-Open No. 2012-255646, for example.
In Japanese Patent Laying-Open No. 2012-255646, there is disclosed a heat exchanger including multiple cores, spacer portions arranged between bonded surfaces of the adjacent cores, and a header portion. In the cores, two types of flow path portions through which two types of fluids flow, respectively, are alternately stacked. The cores each have a rectangular parallelepiped shape, the spacer portions each are formed in an L-shape along two sides of each of the outer peripheral edges of the bonded surfaces of the cores, and the outer peripheral portions thereof are welded to the bonded surfaces of the adjacent cores.